109 chassis, front support pillars for utility tub - weld or bolt?

[tugboat]

2a rebuild...

Ok, so now I have collected the un-used galvanised chassis I managed to pick up as a real bargain. But ... as I knew beforehand, it's for a station wagon and my old 2a is a utility.

As posters have already replied to my previous query, there's not a lot in it. The main issue is in relation to the front two pairs of tub/body supports which produce a platform which is level with the rear four pairs for the utility, but are lowered for the passenger floor area in the case of the SW.

I'd like to keep the option of fitting a station wagon body in the future without more hacking and re-welding, even if the chances are remote. More important, I'd rather not weld the supports from my old chassis through my nice new galvanising.

So here's the question. For MOT purposes, in place of the forward pairs of floor support brackets for the utility, can I get away with welding up some removeable box-section support frames to be through-bolted to the chassis rails? I'm thinking of a pair of bridges spanning the chassis rails.

Without going OTT, it would be easy enough to make up supports and bolting arrangements many times stronger than the original, which isn't saying all that much. And btw, stress analysis of bracketry including, briefly, airframes - aka just loads of brackets flying in formation - was my daily grind for a spell, so designing out the strength problem isn't an issue. The problem is simply whether an MOT tester will reject bolted joints at the chassis rails in place of welded brackets, even although the next joint along the load path, at the tub floor, is a bolted connection anyway.

[Gazzar]

Doubt it. Presuming it looks well fabricated it should be fine, for now.

Of course, when the EU introduces the "no modification" rule then you will be in bother, but you'll be one of thousands made criminals overnight.

G.

[Scooby Jim]

As the body is separate to the chassis as long as the chassis mounts are strong and the hole they bolt into are again strong then you'll be fine.

As the bracket you make up will be the body, and as long as the mounts are well made and strong it can`t really fail.

My Sportrak I just sold had 3 inch plastic spacer blocks, and the MOT man said that as long as the chassis brackets are ok, and there floor where the spacer makes contact is sound then its fine.

So if you could find some way of using the SW body mounts then your onto a winner.

[Phil Hancock]

Dont forget that the brackets on the front fuel tank rear outriggers are different between stw and utility bodies.

[tugboat]

Yet again, many thanks to all for helpful replies. Box section bridge it's most likely to be then. I'll have a look first at the possibility of fitting spacers above the SW supports which would dead simple if it's do-able and structurally stable.

Re the tank, Phil, I'm still to look at that. My old car has the standard 2a 109 filler behind the driver's door and the tank under the seat whilst the new chassis is set up for a rear tank. I see Marsland are selling a "front tank mounting outrigger ... bolt or weld on" for the 88" and I'm wondering whether it would serve the purpose. I might go for a two tank option, having been stuck more than once in the in the middle of the night, back in the days when the old 109 was still fit for long trips; 10 gallons in the front tank, isn't it? Two tanks might even allow for a dual-fuel diesel / "Mazola" option!

[Phil Hancock]

^{The brackets i refer to will foul a std front tank if you try to fit one.}

[Gazzar]

yES, THAT'S RIGHT. sorry caps lock!

Anyway - I've seen where the standard front tank is "adjusted" with a large hammer to fit the SW chassis. Not pretty, but one option.

G.

[Snagger]

Have a look at the back end of a Defender chassis - they have bridges much like you propose where the chassis swoops down between the rear spring mounts and rear cross member. As long as the bridges are laterally strong enough, which would just mean having a deep enough drop to be bolted twice on each leg with at least a 2" spacing or are single bolted with legs on each side of the chassis rail (ie. four legs per bridge), then all should be fine.

As pointed out, the trouble could be impending changes to the MoT regs, so I'd make hoops that mimic the originals with flanges to bolt to the face of the chassis, or better still, just weld the original hoops from the first chassis in place and use brush-on galvafroid or zinc-rich primer and generously spray the inside of the chassis rails with cavity wax (Dinitrol is the best on clean surfaces). Then paint the whole chassis in Schutz - it's horrible stuff but is extremely effective and won't chip or flake. It'll make the chassis last indefinitely rather than just a few decades, will create less interest from the sticky-fingered and will help the vehicle look standard for those new MoT proposals.

[tugboat]

Tank needs attention too, then.

That's interesting about the Defender chassis supports - I'll have a look.

As far as the threatened changes to MOT / Construction and Use, etc., go, there seem to be widely varying views as to whether they will actually affect the UK so I might take my chance on that. Although I WILL hang on to the supports from the old frame.

As far as paint goes, I've been looking at the various types of marine epoxy from Jotun. Scouting around the web, I've come across a few cases where Jotun has been used for underbody or chassis painting of preserved cars and the reports are good. Dinitrol seems to be the protection to use for internals. Back in my yoof, I found a NOS shell for a Morris Oxford which had been dry stored 15 years and which, at the start of the rebuild, I Waxoyled heavily (I bought a 5 gallon drum of the stuff!) inside all the sections, and undersealed the whole underbody and then Waxoyled over the underseal. It eventually rusted away like the rest and in all the usual areas - sills, inner sills, jacking points, outriggers, wings/A-pillars, door skins, floors, etc. - despite my having given all the known areas extra special attention. I reckon it didn't add more than 3 or 4 years to the shell's life over the normal BMC treatment (which, admittedly, was about 50% extra life for a BMC car in my part of the world). But, in short, based on that fairly big experiment, I'm not a fan of Waxoyl.

[Snagger]

Just a thought about those support hoops - instead of cutting them cleanly off the chassis through their welds, cut the chassis rails an inch or so away from the hoops so that you have a pre-welded mounting plate. Then you just need to drill bolt holes and fir the new chassis with rivnuts. As long as you thoroughly grease the inside of the joint, it should last well.

[tugboat]

Rivnuts! Cheers! That should make life really simple.

By the way, I used to find a dollop of Castrol CL chassis grease was the best for long-term maybe/never dismantling precautions like this.